<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/animate.css/4.1.1/animate.min.css" />
    <style>
        .parent {
            width: 300px;
            height: 300px;
            background-color: #ccc;
            /* 水平居中 */
            margin: 0 auto;
            display: flex;
            align-items: flex-end;

        }

        .parent>div {
            width: 60px;
            height: 60px;

        }

        .parent>div:nth-child(2) {
            /* 设置自身在交叉轴对齐方式
        flex-start/end center
        baseline strecth */
            align-self: center;
        }
    </style>
</head>

<body>
    <div class="parent">
        <div class="div1" style="background-color: red;">弹性元素1</div>
        <div class="div2" style="background-color: green;">弹性元素2</div>
        <div class="div3" style="background-color: blue;">弹性元素3</div>

    </div>
    <div style="width: 100px; height: 100px; background-color: red;" class="animate__animated animate__backInDown">我是animateDIV</div>
</body>

</html>